You don't need a tool like that.
Take the rifle out and set the bipod on a hard surface like a kitchen floor. I find my proper spacing and eye relief with the scope in the ring bottoms and then put a small piece of scotch tape on the scope to mark where it should be in the ring.
Once proper spacing is set, torque ring bottoms to base with rings pushed forward towards muzzle so the cross piece in ring is pushes against the front of the base cross slot.
Now use a small level on the base and level the rifle. This is where a canting bipod that can be locked in place like a Harris BRM-S is a great help. With friction leg Harris bipods it can be set that way as well. With the notched legs set it into a notch as it's a more solid feel than the springy bottom. Also the rifle doesn't have to be front to back level. Just side to side. The butt of the rifle can be setting on the ground.
Set the scope into the rings gently as not to mess with rifle being level.
Take one ring top and place it on the ring bottom. Place the level on the top of the elevation knob and gently turn scope until level. Now just tighten two screws on that ring top as they are just being used to hold the scope in place. You can use a small "L" torx wrench that came with the rings and hold the small side of the "L" when doing it. Do one side a little then the other while watching the level to make sure it stays level as the scope will rotate slightly when tightening.
Once tight you can take the level off and install the other ring cap using all 4 ring cap screws and a torque wrench making sure to have close to the same space between top and bottom of the ring on each side. Once done loosen the other 2 ring cap screws and properly torque all 4 down like the other one. Done.
Then do to the range and hang a plumb level and check to make sure the scope is mounted level and you are done. Everything I typed above works and takes about 10 minutes after you do it 15-20 times
